M. Ya. Khil'ko

Nucleophilic addition to acetylenes in superbasic catalytic systems: XI. Transformations of alkali metal hydroxides during vinylation of 1-heptanol with acetylene under elevated pressure

Base-catalyzed addition of 1-heptanol to acetylene under elevated pressure of the latter is accompanied by side processes including formation of carboxylic acid salts (alkali metal heptanoates and acetates) with liberation of hydrogen and acetylene polymerization. The rate of acetylene absorption depends on the alkali metal nature and falls down in the series CsOH·H2O ≥ RbOH·H2O > 2KOH·H2O > NaOH > LiOH. Approximately the same order is observed for variation of the rate of deactivation of the catalyst owing to its transformation into metal carboxylate. Dehydration of the catalyst accelerates both vinylation and acetylene polymerization.

Solvatochromism of Heteroaromatic Compounds: XXI. Ion Pairs of 4-Nitropyrazolide Anion

The solvatochromism of the long-wave UV absorption band of the contact ion pairs of the 4-nitropyrazolide anion with alkali metal cations in aprotic protophilic solvents with ε ≤ 24 was studied and quantitatively described using the Kamlet-Taft empirical solvent parameters. Of two possible types of tight ion pairs differing in the murtual arrangement of the counterions, the solvent stabilizes the pair in which the cation is located in the σ plane of the anion in the vicinity of its nitrogen atoms. Among the factors affecting the quantitative characterisitcs of the solvatochromism of such ion pairs, the major factors are the polarity/polarizability of the solvent and the capability of its molecules for coordination with cations. The peripheral specific solvation of the cation in an ion pair stabilizes its Franck-Condon excited state relative to the ground electronic state. In the quantitative respect, this effect is similar to that characteristic of solvation H complexes.

Environmentally benign (Green) synthesis of Cobazole, an efficient erythropoiesis-stimulating agent

A practicable and environmentally benign process for the synthesis of Cobazole, an erythropoiesisstimulating agent, has been developed. The process is based on the reaction of N-vinylimidazole with cobalt chloride in water and requires no toxic organic solvents, which ensures the preparation of high-purity product.

Polyethylene oxide—polysiloxane branched copolymers and networks

The hydrosilylation of vinyl methyl and divinyl ethers of oligoethylene glycols with polyhydridosiloxanes in the presence of chloroplatinic acid is accompanied by side processes, namely, polymerization of vinyl ethers and homodehydrocondensation of polyhydridosiloxanes. The electrical conductivity of ∼1M solutions of lithium triflate or bis(trifluoromethylsulfonyl) imide in the resulting hydrosilylation products is ∼10−5 S cm−1.

Calculation of the torsional angles in alkyl vinyl ethers from the direct13C-1H spin-spin interaction constants

It is shown that the differences in the direct13C-1H SSIC of the Cβ atom of the vinyl groups in alkyl vinyl ethers depend on the value of the torsional angle about the Cα bond. This dependence is used to make quantitative estimates of the torsional angles in alkyl vinyl ethers with alkyl substituents ranging from CH3 to t-C4H9

Stereoelegtronic effects in phosphonates

1. n nA study was made of the31P chemical shifts and the1J31P-13C SSCC in a number of phosphonates that contain the same structural fragments in a variable position. n n n n n2. n nThe effect of the stereoelectronic effects, interpreted as the p,σ conjugation of the unshared pairs of the oxygen atoms and the P-C bonds, on the SSCC values of the directly attached31P and13C nuclei was elucidated.

NMR spectra and structure of 2-(2′-chloroethoxy)-2-oxa-3-methyl-1,4,2-dioxaphosphane

1. n nThe configurations and conformations of a new six-membered phosphorus-containing heterocycle 2-(2′-chloroethoxy)-2-oxa-3-methyl-1,4,2-dioxaphosphane were studied by the NMR method. n n n n n2. n nThe value of the geminal SSIC2J31PCH in this compound was determined primarily by the mutual orientation of the proton and phosphoryl groups.